What is music21?
Music21 is a set of tools for helping scholars and other active listeners answer questions about music quickly and simply. If you’ve ever asked yourself a question like, “I wonder how often Bach does that” or “I wish I knew which band was the first to use these chords in this order,” or “I’ll bet we’d know more about Renaissance counterpoint (or Indian ragas or post-tonal pitch structures or the form of minuets) if I could write a program to automatically write more of them,” then music21 can help you with your work.
How simple is music21 to use?
Extremely. After starting Python and typing "from music21 import *" you can do all of these things with only a single line of music21 code:
Display a short melody in musical notation:
converter.parse("tinynotation: 3/4 c4 d8 f g16 a g f#").show()
Print the twelve-tone matrix for a
tone row (in this case the opening of Schoenberg's Fourth String Quartet):
print (serial.rowToMatrix([2,1,9,10,5,3,4,0,8,7,6,11]) )
Convert a file from Humdrum's **kern data format to MusicXML for editing in Finale or Sibelius:
With five lines of music21 code or less, you can:
Prepare a thematic (incipit) catalog of every Bach chorale that is in 3/4:
for workName in corpus.getBachChorales():
work = converter.parse(workName)
firstTS = work.flat.getTimeSignatures()
if firstTS.ratioString == '6/8':
Google every motet in your database that includes the word ‘exultavit’ in the superius (soprano) part (even if broken up as multiple syllables in the source file) to see how common the motet's text is:
for motet in listOfMotets:
superius = motet
lyrics = text.assembleLyrics(part)
if 'exultavit' in lyrics:
webbrowser.open('http://www.google.com/search?&q=' + lyrics)
Add the German name (i.e., B♭ = B, B = H, A♯ = Ais) under each note of a Bach chorale and show the new score:
for thisNote in bwv295.flat.notes:
Of course, you are never limited to just using five lines to do tasks with music21. In the demos folder of the music21 package and in the sample problems page (and throughout the documentation) you’ll find examples of more complicated problems that music21 is well-suited to solving, such as cataloging the rhythms of a piece from most to least-frequently used.
Music21 builds on preexisting frameworks and technologies such as Humdrum, MusicXML, MuseData, MIDI, and Lilypond but music21 uses an object-oriented skeleton that makes it easier to handle complex data. But at the same time music21 tries to keep its code clear and make reusing existing code simple. With music21 once you (or anyone else) has written a program to solve a problem, that program can easily become a module to be adapted or built upon to solve dozens of similar (but not identical) problems.
Interested in learning more?
- Get Started with music21
- Browse the music21 documentation
- Download music21 from GitHub
- Get our latest news and updates at the music21 blog
- Read the Frequently Asked Questions list
- Sign up for the music21list mailing list through Google Groups.
I am a researcher within the Performing Arts Medicine Association. I was interested in looking at Beethoven's use of range over time in his piano sonatas. Although several previous studies have looked at the question of how Beethoven's compositions were affected by his hearing loss, the results were far less than conclusive. A study in the British Medical Journal counted the notes in the first movements of the first violin parts of Beethoven's string quartet's by hand. For a number of reasons, I thought it might be better to look at the piano sonatas, including that Beethoven wrote more piano sonatas than he did string quartets and symphonies, so the statistical power would be greater. Counting all of the notes in Beethoven's piano sonatas by hand would be a Herculean task for sure, but fortunately with scores available from the Center for Computer Assisted Humanities and music21 sufficient coding skills would do the job.
In addition to the number of high notes, I was also interested in Beethoven's overall use of range, the average note, average frequency, number of measures with high notes, and in calculating values based on the number of notes, as well as weighting those measures by the duration of notes. The methods available in music21 allow the collection of this data very quickly. To collect the majority of the data I needed from all 103 movements of Beethoven's piano sonatas, count over a quarter million individual notes, and organize the data into sonatas, and separating the data by movement number, takes about 11 minutes.
Some Interesting Findings
Beethoven's use of high notes was lowest around 1800 (for all the graphs below, the colors within the dots represent the Sonata Numbers, going from red to purple from 1-32):
The average frequency of each sonata follows a similar trend:
In general, as there are more notes per measure, there are more high notes per measure. This trend does not hold many of the sonatas written before 1802.
Also, the relationship between the use of high notes, and the average frequency was different between the earlier and later sonatas:
Technology like music21 is an invaluable tool for the empirical study of musicology. Relatively quickly, data gathered can be used to analyze the possible relationships between Beethoven's use of high notes and his overall range, and compare that with what we understand about his hearing loss. These data suggest that Beethoven was significantly affected by his hearing loss, though it seems that sometime around 1802 he developed strategies to cope with his progressing disability.
While everyone says that in Python you can import a module inside a function without it going through the overhead of actually reimporting, there is some real overhead still, especially if the function is called a lot of times:
In music21 you can easily plot the position of notes as a piano roll:
which preserves pitch names, measure numbers, etc. But the case we're asking for requires a plot more like this:
The numbers at the left are midi numbers while the bottom is number of quarter notes from the beginning. Here's some code to help you achieve this:
With this sort of graph it's easy to isolate each voice (not much overlap of voices in this chorale) and to see the preponderance of similar motion among the Soprano, Alto, and Tenor, but lack of coordination with the Bass (which would create forbidden parallels if it coordinated). More sophisticated examples with better labels are easily created by those with knowledge of matplotlib, but this simple demonstration will suffice to get things started.
How can I contribute?
Music21 is a rapidly-progressing project, but it is always looking for researchers interested in contributing code, questions, freely-distributable pieces, bug fixes, or documentation. Please contact Michael Scott Cuthbert (cuthbert at mit.edu), Principal Investigator.
The development of music21 has been supported by the School of Humanities, Arts, and Social Sciences at M.I.T., the Music and Theater Arts section, and generous grants from the Seaver Institute and the NEH/Digging-Into-Data Challenge. Further donations to the project are always welcome.